|February 3, 2014, 07:59||
Continuing an LES simulation at large Co
Join Date: May 2013
Location: Southampton, UK
Posts: 293Rep Power: 7
I have recently switched from using U-RANS to LES simulating unsteady flow around mariner propellers. I am interested in having long time-traces of data and so restarting my simulations multiple times is a must, given maximum walltime of 60 hours per job on the cluster I have access to.
I tend to run my simulations at maxCo of about 2.5, starting from a mapped RANS solution. Everything works just fine in the first run. However, when I restart there is a short period of time (5-10 time steps, sometimes more) where forces values become completely unphysical, solvers take far more iterations to converge and adaptive time step falls down by about a factor of 10. After this period things seem to recover and everything works just as well as it did during the first run. I tried various scheme/solver/subgrid model configurations with no effect. The only thing that seems to have an effect is manually editing the deltaT value in the last time directory and setting it to a small value, like the one I used at the beginning of the first run (~1e-7 s).
Question is: If I record time traces of forces on the blades, pressures at various locations, etc., how will I know what part of them to discard due to these perturbations exactly and how may I be sure that these will not affect the flow in some weird way (create/destroy vortices, low/high pressure regions, you get the point)?
|Thread||Thread Starter||Forum||Replies||Last Post|
|Reversed flows in Large Eddy Simulation||luc89ita||FLUENT||0||August 3, 2013 07:15|
|How to conduct transient LES simulation||tianrenshui311||FLUENT||0||November 15, 2010 14:21|
|LES simulation of bluff body at Re(d)=1200||arash_nl||FLUENT||0||June 1, 2009 13:16|
|Need LES simulation knowledge / reference material||Sam||CFX||7||January 25, 2008 17:30|
|Flow around the ahmed body (large eddy simulation)||Benzamia||CFX||0||February 26, 2007 06:03|